Light source device and projection display device

ABSTRACT

The light source device includes a laser for generating laser light, a fluorescent wheel, a filter wheel and a control unit. The fluorescent wheel includes a reflection section, and a transmission section. First and second phosphors are attached on a surface of the reflection section, and the first phosphor is excited by the laser light to emit yellow light and the second phosphor is excited by the laser light to emit green light. The filter wheel comprises a transparent section, a red filter section and a green filter section. The control unit controls the fluorescent wheel and the filter wheel to rotate in synchronization. the laser light emitted from the transmission section of the fluorescent wheel and a part of the yellow light enter into the transparent section, another part of the yellow light enter into the red filter section, and the green light enter into the green filter section.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/688,715 filed Apr. 16, 2015, which claims the priority to ChinesePatent Application No. 201410556532.3, filed with the State IntellectualProperty Office on Oct. 20, 2014, the content of which is herebyincorporated by reference in its entirety.

FIELD

The present disclosure relates to the field of laser light sources andparticularly to a light source device and a projection display device.

BACKGROUND

A high-pressure mercury lamp (which is a high-intensity gas dischargelight source) applied in a traditional projection display product(simply a projector) as a projection light source has been increasinglyreplaced with a new light source due to its short lifetime, high cost ofreplacing a bulb, highly poisonous mercury, etc., and here the laserlight source which is a solid light source has become an emerging optionof the projection light source due to a series of advantages of highbrightness, high efficiency, a long lifetime, a good color gamut,environment protection, etc. In the meanwhile, laser projector productsalso have become new customer electronic products popular amongcustomers as projection display products have their applicationsextending gradually from meeting rooms to homes.

Typically a laser light source is provided with laser light to excitephosphors to generate light in three primary colors. For example, thephosphors, attached on a fluorescent wheel, capable of being excited bythe laser light to emit light, are excited by the laser light togenerate light at corresponding wavelengths, which may be filteredresulting in the three primary colors. Natural colors may be generatedby synthesizing the three red, green and blue colors in differentproportions, so a color picture may be displayed by a projection displayproduct as a result of synthesizing the light in the three primarycolors.

SUMMARY

In one aspect, some embodiment of the disclosure provide a light sourcedevice including a laser for generating laser light, a fluorescentwheel, a filter wheel and a control unit. The fluorescent wheel includesa reflection section, and a transmission section for transmitting thelaser light. A first phosphor and a second phosphor are attached on asurface of the reflection section, and the first phosphor is configuredto be excited by the laser light to emit yellow light and the secondphosphor is configured to be excited by the laser light to emit greenlight. The filter wheel comprises a transparent section, a red filtersection and a green filter section. The control unit is configured tocontrol the fluorescent wheel and the filter wheel to rotate insynchronization, and the laser light emitted from the transmissionsection of the fluorescent wheel and a part of the yellow light emittedfrom the first phosphor enter into the transparent section of the filterwheel, another part of the yellow light emitted from the first phosphorenter into the red filter section of the filter wheel, and the greenlight emitted from the second phosphor enter into the green filtersection of the filter wheel.

In another aspect, some embodiments of the disclosure further provide aprojection display device including a laser for generating laser light,a fluorescent wheel, a filter wheel and a control unit. The fluorescentwheel includes a reflection section, and a transmission section capableof transmitting the laser light. A first phosphor and a second phosphorare attached on a surface of the reflection section, and the firstphosphor is configured to be excited by the laser light to emit yellowlight and the second phosphor is configured to be excited by the laserlight to emit green light. The filter wheel comprises a transparentsection, a red filter section and a green filter section. The controlunit is configured to control the fluorescent wheel and the filter wheelto rotate in synchronization, and the laser light emitted from thetransmission section of the fluorescent wheel and a part of the yellowlight emitted from the first phosphor enter into the transparent sectionof the filter wheel, another part of the yellow light emitted from thefirst phosphor enter into the red filter section of the filter wheel,and the green light emitted from the second phosphor enter into thegreen filter section of the filter wheel.

Moreover some embodiments of the disclosure further provide a projectiondisplay device including a laser for generating laser light, afluorescent wheel, a filter wheel and a control unit. The fluorescentwheel includes a reflection section, and a transmission section fortransmitting the laser light. A first phosphor and a second phosphor areattached on a surface of the reflection section, and the first phosphoris configured to be excited by the laser light to emit a first light ina first band, and the second phosphor is configured to be excited by thelaser light to emit a second light in a second band. The filter wheelcomprises a transparent section, a first filter section and a secondfilter section. The control unit is configured to control thefluorescent wheel and the filter wheel to rotate in synchronization, andthe laser light emitted from the transmission section of the fluorescentwheel and a part of the first light emitted from the first phosphorenter into the transparent section of the filter wheel, another part ofthe first light emitted from the first phosphor enter into the firstfilter section of the filter wheel, and the second light emitted fromthe second phosphor enter into the second filter section of the filterwheel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic structural diagram of a beam shapingdevice;

FIG. 2 illustrates a mechanical diagram of the beam shaping device;

FIG. 3 illustrates a fluorescent wheel according to some embodiments ofthe disclosure;

FIG. 4 illustrates a filter wheel according to some embodiments of thedisclosure;

FIG. 5 illustrates a diagram of a correspondence relationship between afluorescent wheel and a filter wheel according to some embodiments ofthe disclosure;

FIG. 6 illustrates a fluorescent wheel according to some furtherembodiments of the disclosure;

FIG. 7 illustrates a filter wheel according to some further embodimentsof the disclosure;

FIG. 8 illustrates a diagram of a further correspondence relationshipbetween a fluorescent wheel and a filter wheel according to some furtherembodiments of the disclosure;

FIG. 9 illustrates a schematic structural diagram of a light sourcedevice according to some embodiments of the disclosure;

FIG. 10 illustrates a schematic diagram of a spectrum of red lightfiltered out in the light source device according to some embodiments ofthe disclosure;

FIG. 11 illustrates a schematic diagram of a spectrum of green lightfiltered out in the light source device according to some embodiments ofthe disclosure;

FIG. 12 illustrates a schematic diagram of a color gamut as a result ofsynthesizing four primary colors generated by the light source deviceaccording to some embodiments of the disclosure;

FIG. 13 illustrates a schematic diagram of a spectrum of red lightfiltered from red light emitted by an excited phosphor excited by thelaser light to emit red light according to some embodiments of thedisclosure; and

FIG. 14 illustrates a light emission efficiency graph of an excitedphosphor excited to emit yellow light and an excited phosphor excited toemit red light according to some embodiments of the disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In order to make the objects, technical solutions and advantages of thedisclosure more apparent, the disclosure will be further described belowwith reference to the drawings, and apparently the embodiments describedbelow are only a part but not all of the embodiments of the disclosure.All the other embodiments which may occur to those ordinarily skilled inthe art based upon the embodiments here of the disclosure without anyinventive effort shall fall into the claimed scope of the disclosure.

Some embodiments of the disclosure provide a light source device (notillustrated) including a laser for generating laser light, a fluorescentwheel, a filter wheel and a control unit, where the fluorescent wheelincludes at least one reflection section, and at least one transmissionsection capable of transmitting the laser light; at least one phosphorcapable of being excited by the laser light to emit light in a firstwavelength band, and at least one phosphor capable of being excited bythe laser light to emit light in a second wavelength band are attachedon the surface of the reflection section; the filter wheel includes atleast one transparent section, at least one first filter section and atleast one second filter section; and the control unit is configured tocontrol the fluorescent wheel and the filter wheel to rotate insynchronization so that the transparent section of the filter wheelcorresponds to the transmission section of the fluorescent wheel, and apart of the phosphor, on the fluorescent wheel, excited by the laserlight to emit the light in the first band, the first filter section ofthe filter wheel corresponds to another part of the phosphor, on thefluorescent wheel, excited by the laser light to emit the light in thefirst band, and the second filter section of the filter wheelcorresponds to the phosphor, on the fluorescent wheel, excited by thelaser light to emit the light in the second band.

The light in the first band and the light in the second band may bevisible light applicable to the inventive solution, for example, thelight in the first band may be yellow light, green light, etc.; and thelight in the second band may be green light, yellow light, red light,etc. Moreover the first filter section may be a red filter section, agreen filter section, etc., and the second filter section may be a greenfilter section, a red filter section, etc.

In order to make the solution according to the embodiment above of thedisclosure more apparent, it will be described below by way of anexample in which the light in the first band is yellow light, the lightin the second band is green light, the first filter section is a redfilter section, and the second filter section is a green filter section.

As illustrated in FIG. 9, a light source device according to someembodiments of the disclosure includes a laser for generating laserlight, a fluorescent wheel 23, a filter wheel 26 and a control unit (notillustrated).

As illustrated in FIG. 3, the fluorescent wheel may include a reflectionsection 32, and a transmission section 31 capable of transmitting thelaser light, and phosphors 321 and 322 capable of being excited by thelaser light to transmit light in two different colors are attached onthe surface of the reflection section. As illustrated in FIG. 4, thefilter wheel may include a transparent section 41, and filter sections42 and 43 in two colors; and the control unit may be configured tocontrol the fluorescent wheel and the filter wheel to rotation insynchronization.

The light source device may further include a beam shaping device(including a reflection mirror 12, a convex lens 13 and a concave lens14), a first optical axis transformation lens 21 and a light convergingdevice; the beam shaping device may shape the laser light; the firstoptical axis transformation lens may be arranged between the beamshaping device and the fluorescent wheel to transmit the shaped laserlight and to reflect fluorescent light from the fluorescent wheel; thelight converging device may include a plurality of optical axistransformation lenses and a focusing lens 27; the plurality of opticalaxis transformation lenses may be configured to change a light path ofthe shaped laser light transmitted through the transmission section ofthe fluorescent wheel; and the focusing lens may focus the lightreflected and the light transmitted by the first optical axistransformation lens onto the same light path.

As illustrated in FIG. 1 and FIG. 2, the laser may include laser arrays11 at low power, so that when the power of the laser light is up to tensof watts or higher, the laser light may be shaped (e.g., thetransmission direction of the light beam is changed, the light issynthesized, the light is focused, or the light path is transformed) bythe beam shaping device (also referred to as a light synthesizing lens)including the reflection mirror 12, the convex lens 13 and the concavelens 14, arranged at 45° from both of the laser arrays, and the shapedlaser light may in turn excite the phosphors to emit fluorescent light.

With the light source device according to the embodiment above of thedisclosure, after the laser light is shaped by the beam shaping device,the shaped laser light excites the phosphors on the fluorescent wheel,the phosphors are excited to emit fluorescent light which is reflectedby the first optical axis transformation lens and focused by thefocusing lens and then irradiated on the filter wheel, and the filterwheel transmits the shaped laser light and filters out light in threecolors from the fluorescent light to thereby generate light in fourprimary colors. As illustrated in FIG. 5, a phosphor, on the fluorescentwheel, capable of being excited to emit fluorescent light corresponds toa transparent section and a filter section on the filter wheel, and whenthe phosphor is excited by the shaped laser light to emit fluorescentlight, the transparent section may transmit light in a colorcorresponding to a primary spectrum included in the band of thephosphor, and the filter section filters out light in a colorcorresponding to a spectrum of an adjacent band included in the band ofthe phosphor; another phosphor, on the fluorescent wheel, capable ofbeing excited to emit fluorescent light corresponds to a filter sectionon the filter wheel, and when the another phosphor is excited by theshaped laser light to emit fluorescent light, light in a colorcorresponding to a primary spectrum in the band of the another phosphoris filtered out; and the transmission section on the fluorescent wheelcorresponds to the transparent section on the filter wheel to therebytransmit the shaped laser light, so that finally the light in the fourprimary colors may be generated from a light emission face of the filterwheel according to the setting on and the correspondence relationshipbetween the fluorescent wheel and the filter wheel. The light in thefour primary colors may be synthesized into a number of colors in awider color gamut for a technical effect of wider color gamut of thelight source device as compared with synthesis of the three primarycolors into a number of colors.

In the light source device according to some embodiments of thedisclosure, a phosphor capable of being excited by the laser light toemit yellow light, and a phosphor capable of being excited by the laserlight to emit green light are attached on the surface of the reflectionsection of the fluorescent wheel, and the laser light may be in blueband. As may be apparent from the spectrum of natural light, the yellowband includes a part of the spectrum of light in red band, so thephosphors are excited by the laser light to emit yellow fluorescentlight and green fluorescent light which may be further reflected by thefirst optical axis transformation lens and then focused by the focusinglens to be irradiated on the filter wheel and thus transmitted andfiltered by the filter wheel.

In some embodiments of the disclosure, the transparent section of thefilter wheel corresponds to the transmission section of the fluorescentwheel, and a part of the phosphor, on the fluorescent wheel, excited bythe laser light to emit yellow light; the red filter section of thefilter wheel corresponds to another part of the phosphor, on thefluorescent wheel, excited by the laser light to emit yellow light; andthe green filter section of the filter wheel corresponds to thephosphor, on the fluorescent wheel, excited by the laser light to emitgreen light.

The phosphor, on the fluorescent wheel, capable of being excited to emityellow fluorescent light corresponds to the transparent section and thered filter section on the filter wheel, and when the phosphor is excitedby the laser light to emit yellow fluorescent light, the transparentsection may transmit yellow light, and the red filter section may filterout red light from the yellow fluorescent light.

The other phosphor, on the fluorescent wheel, capable of being excitedto emit green light corresponds to the green filter section on thefilter wheel, and when the phosphor is excited by the laser light toemit green fluorescent light, purer green light may be filtered out. Asillustrated in FIG. 11, the solid line represents the spectrum of thegreen light filtered out by the green filter section, whereas the dottedline represents the spectrum of the green light which has not beenfiltered yet, and apparently the purer green color may be filtered outby the filter section so that the green color may appear more distinctin a color picture.

The transmission section on the fluorescent wheel corresponds to thetransparent section on the filter wheel to thereby transmit the bluelaser light.

In summary, in some embodiments of the disclosure, the red light isfiltered out by the red filter section of the filter wheel from a partof the yellow light, the green color becomes purer due to the greenfilter section (a narrower width of the spectrum represents a purercolor), the other part of the yellow light is transmitted directlywithout being filtered, and the blue laser light is also transmitteddirectly, thus resulting in the light in four colors in total. With thesetting on and the correspondence relationship between the fluorescentwheel and the filter wheel, finally the four primary colors of yellow,red, green and blue are generated from the light emission face of thefilter wheel; and the light in these four colors may be synthesized intoa number of colors. In the spectrum diagram as illustrated in FIG. 12,the dotted line zone in the horseshoe-shaped spectrum color gamutrepresents a color gamut range of colors into which three primary colorsare synthesized in the prior art, whereas the solid line zone representsa color gamut range of colors into which the four primary colors aresynthesized in some embodiments of the disclosure, and apparently thereis a wider color gamut of the light source device according to someembodiments of the disclosure.

FIG. 6 to FIG. 8 illustrates the structure of and the correspondencerelationship between the fluorescent wheel and the filter color in somefurther examples thereof according to some further embodiments of thedisclosure.

In the fluorescent wheel, the numbers of transmission section 31,phosphors 321 excited by the laser light to emit yellow light, andphosphors 322 excited by the laser light to emit green light may be tworespectively, and here the two transmission sections may be centrallysymmetrically distributed, the two phosphors excited by the laser lightto emit yellow light may be centrally symmetrically distributed, and thetwo phosphors excited by the laser light to emit green light may becentrally symmetrically distributed. In the filter wheel, the numbers oftransparent sections 41, red filter sections 42 and green filtersections 43 may be two respectively, and here the two transparentsections may be centrally symmetrically distributed, the two red filtersections may be centrally symmetrically distributed, and the two greenfilter sections may be centrally symmetrically distributed.

Optionally one transmission section, one phosphor excited by the laserlight to emit yellow light, and one phosphor excited by the laser lightto emit green light occupy together one half circle; and one transparentsection, one red filter section and one green filter section occupytogether one half circle.

In some embodiments of the disclosure, in the fluorescent wheel, thetransmission section, the phosphor excited by the laser light to emityellow light, and the phosphor excited by the laser light to emit greenlight occupy sequentially the angles of 28°, 93° and 59° in the halfcircle respectively; and in the filter wheel, the transparent section41, the red filter section 42 and the green filter section 43 occupysequentially the angles of 51°, 70° and 59° in the half circlerespectively.

There may be such a mirrored correspondence relationship between thefluorescent wheel and the filter wheel that the transparent section 41of the filter wheel corresponds to the transmission section 31 (28°) anda part of the phosphor 321 (23°) excited by the laser light to exciteyellow light, of the fluorescent wheel, the red filter section 42corresponds to the remaining phosphor 321 (70°) excited by the laserlight to excite yellow light, and the green filter section 43corresponds to the phosphor 322 (59°) excited by the laser light toexcite green light.

The laser light is in blue band. Further to the description above, thelaser light transmitted from the transmission section of the fluorescentwheel is transmitted through the transparent section of the filterwheel; for the light in yellow band emitted as a result of excitation bythe laser light, the part thereof corresponding to the transparentsection of the filter wheel is transmitted through the transparentsection of the filter wheel as yellow light, and the part thereofcorresponding to the red filter section of the filter wheel is filteredout and transmitted through the red filter section as red light; and forthe light in green band emitted as a result of excitation by the laserlight, the corresponding green light is filtered out by the green filtersection of the filter wheel, so that the light transmitted through thefilter wheel includes the laser light in blue band, the yellow light,the red light and the green light.

When a phosphor is excited for conversion into light energy at acorresponding wavelength, the efficiency of conversion becomes lower ata longer wavelength, so in the embodiments of the disclosure, the redlight is filtered out by the red filter section from the yellowfluorescent light, and since the wavelength of the yellow light isshorter than the wavelength of the red light, there will be higher lightenergy of the red light filtered out from the yellow light generated bythe excited phosphor excited by the laser light to emit yellow light, ascompared with the red light generated by the excited phosphor excited bythe laser light to emit red light.

The reason for the improvement in light emission efficiency of the redlight and thus the improvement in overall brightness of the light sourcedevice in the embodiments above of the disclosure will be describedbelow.

With the light source device according to some embodiments of thedisclosure, there will be higher light emission efficiency of the redlight filtered out from the yellow light emitted by yellow fluorescentpowder (the phosphor coated on the fluorescent wheel to emit the yellowlight upon being excited by the laser light) excited by the laser lightin the embodiments of the disclosure as compared with the red lightfiltered out from the red light emitted by the red fluorescent powder(the phosphor coated on the fluorescent wheel to emit red light uponbeing excited by the laser light) excited by the laser light in theprior art, as depicted In Table-1, Table-2 and Table-3 below, forexample.

TABLE 1 Brightness Brightness of the light proportion of emitted byPreset angles the filtered-out the light on the fluorescent wheel redlight in the source Red/ Schemes white light (lm/lumen) Yellow YellowGreen Blue Red 7.64% 8257 23 70 59 28 fluorescent powder Yellow 7.64%9695 31 56 65 28 fluorescent powder Yellow 11.30% 8706 23 70 59 28fluorescent powder

As may be apparent from Table-1 above, in the scheme with the redfluorescent powder, and with the yellow fluorescent powder at 23°, thered fluorescent powder at 70°, the green fluorescent powder at 59°, andthe blue fluorescent powder at 28°, the four-primary color schemeachieves the overall brightness of 8257 lm of the white light (the lightinto which the four primary colors are synthesized) emitted by the lightsource device, under the circumstance that the brightness proportion(the brightness proportion of the red light in the white light) is7.64%; and with the same setting of the angles (i.e., 23°, 70°, 59° and28° as described above) except for the yellow fluorescent powder insteadof the red fluorescent powder (of course, the filter wheel will beadjusted accordingly to the scheme where the red light is filtered outfrom the yellow light), as may be apparent from Table-1, the brightnessproportion of the red light in the white light is as high as 11.30%.Apparently with the same setting of the angles, there is higher lightemission efficiency, and thus higher brightness, of the red lightfiltered out from the yellow light, and also the overall brightness ofthe light source device may be improved by (8706−8257)/8257=5.43%.

In a practical application, if the red light at a lower brightnessproportion is desirable, then the angles on the fluorescent powders maybe reallocated as needed.

In Table-1 above, with the scheme where the red light is filtered outfrom the yellow light, if the brightness proportion of the red light inthe white light is maintained as the scheme where the red fluorescentpowder is excited (that is, the brightness proportion of the red lightin the white light is 7.64%), then the angle for the red segment may belowered (from 70° to 56°) for allocation to other color segments. Inthis embodiment, for example, the angle of the yellow fluorescent powderfor generating the yellow light is increased by 8°, and the angle of thegreen fluorescent powder for generating the green light is increased by6°, whereas other color segments remain as they are. In this embodiment,the efficiency of conversion in exciting yellow color and green color ismuch higher than the efficiency of conversion in exciting red light(because the wavelengths of all the other color segments are shorterthan the wavelength of the red light), so the overall brightness of thelight source device may be improved by (9695−8257)/8257=17.42% ascalculated from the data in the table.

There are schemes for setting the angles on the fluorescent wheel asdepicted in Table-2 below.

Brightness Brightness of the light proportion of emitted by Presetangles the filtered-out the light on the fluorescent wheel red light inthe source Yel- Red/ Schemes white light (lm/lumen) low Yellow GreenBlue Red 11.30% 7323 18 88 52 22 fluorescent powder Yellow 11.30% 870623 70 59 28 fluorescent powder

As may be apparent from Table-2 above, in the scheme with the redfluorescent powder, there is overall brightness of 7323 lm of the whitelight (the light into which the four primary colors are synthesized)emitted by the light source device, under the circumstance that thebrightness proportion (the brightness proportion of the red light in thewhite light) is 11.30%; and in the scheme where the red light isfiltered out from the yellow light, if the brightness proportion of thered light in the white light is maintained as the scheme where the redfluorescent powder is excited (that is, the brightness proportion in thered light in the white light is 11.30%), then the angle of thefluorescent powder for generating red light may be lowered from 88° to70°, and the remaining angle may be allocated to other colors. Similarto Table-1, the light in the other colors may be provided with moreexcitation energy of the laser light, thus the efficiency of lightenergy and hence the brightness may be improve, and in this scheme, theoverall brightness of the light source device may be improved by(8706−7323)/7323=18.89%. On the other hand, with the scheme where thered light is generated using the original red fluorescent powder, ahigher angle needs to be allocated to the red fluorescent powder, andthere may also a loss of the overall brightness of the light source.

There are other schemes for setting the angles on the fluorescent wheelas depicted in Table-3 below.

Brightness Brightness of the light Proportion of emitted by Presetangles the filtered-out the light on the fluorescent wheel red light inthe source Yel- Red/ Schemes white light (lm/lumen) low Yellow GreenBlue Red 8.70% 8109 25 76 55 24 fluorescent powder Yellow 8.70% 9420 3060 62 28 fluorescent powder Yellow 7.64% 9695 31 56 65 28 fluorescentpowder

As may be apparent from Table-3 above, with the scheme where the redlight is generated using the red fluorescent powder, when the brightnessproportion of the red light in the white light is 8.7%, the angle of thered fluorescent powder is 76°, and the overall brightness of the lightsource is 8109 lm; and with the scheme where the red light is filteredout using the yellow fluorescent powder under the same brightnessproportion of the red light, the angle of the yellow fluorescent powderfor generating the red light is 60°, and the overall brightness of thelight source is 9420 lm, that is, the overall brightness of the lightsource is improved by 16.71%.

In the scheme with the yellow fluorescent powder, when the angle of theyellow fluorescent powder for generating the red light is changed, asmay be apparent from comparison between the second (the total angle ofthe yellow fluorescent powder is 90°) and third (the total angle of theyellow fluorescent powder is 87°) rows in Table-3, when the angle of theyellow fluorescent powder for generating the red light is lowered from60° to 56°, and the remaining angle is added to the green fluorescentpowder for generating the green light and the yellow fluorescent powderfor generating the yellow light, since the green light and the yellowlight may be emitted at higher efficiency and thus higher brightnessalthough the brightness proportion of the red light is lowered, theoverall brightness of the light source device may be improved from 9420lm to 9695 lm.

As may be apparent from the description above, with the technicalsolution according to the embodiment above of the disclosure, the lightemission efficiency of red light may be higher and thus the brightnessof the red light may be higher, given the same angle scheme; and due tothe higher light emission efficiency of the red light, the angle, on thecircle, occupied by the phosphor excited to emit the yellow light may belower than the angle occupied by the phosphor excited to emit the redlight with the same energy efficiency, so that the angles may bereallocated in such a way that the proportions of the phosphors excitedto emit the light in the other colors may be increased as appropriate,and the light in the other colors may be excited at higher energy thanbefore and thus emitted at higher light energy to thereby improve theirlight emission efficiency so that the overall brightness of the lightsource device may be improved.

With the light source device according to the embodiment above of thedisclosure, the red color may appear more distinct in a color picture,the overall brightness of the system may also be improved, and the colorgamut thereof may also be larger than the color gamut of the existingHigh Definition TV set standard by more than 30%.

Moreover there is such an additional effect that there will be purer redlight filtered out from the yellow light emitted by the yellowfluorescent powder (the phosphor, coated on the fluorescent wheel,excited by the laser light to exit the yellow light) excited by thelaser light in the embodiments of the disclosure, as compared with thered light filtered out from the red light emitted by the red fluorescentpowder (the phosphor, coated on the fluorescent wheel, excited by thelaser light to exit the red light) excited by the laser light in theprior art. As illustrated in FIG. 10, for example, there is a schematicdiagram of the spectrum of the red light filtered out by the red filtersection from the yellow light emitted by the excited phosphor, and herethe abscissa represents the wavelength of the light, whereas theordinate represents the strength of the light, and as may be apparentfrom the figure, the dotted line represents the spectrum range of thered light before being filtered (480 nanometers (nm) to 780 nm), and thesolid line represents the spectrum range of the red light filtered outby the red filter section according to some embodiments of thedisclosure (580 nm to 780 nm); and as illustrated in FIG. 13, there is aschematic diagram of the spectrum of the red light filtered out from thered light emitted by the red fluorescent powder excited by the laserlight according to some embodiments of the disclosure, and here thedotted line represents the spectrum range of the red light before beingfiltered, and the solid line represents the spectrum range of the redlight filtered out from the red light emitted by the red fluorescentpowder excited by the laser light (570 nm to 780 nm). As may be apparentfrom comparison between FIG. 10 and FIG. 13, the purity of the red lightfiltered out from the yellow light according to some embodiments of thedisclosure is higher than the purity of the red light filtered out fromthe fluorescent light emitted by the red fluorescent powder (a narrowerwidth of the spectrum represents a purer color).

In some embodiments of the disclosure, the power of the laser light inthe blue band as used above ranges from 70 W to 80 W, and as the powerof the laser light increases, the excitation efficiency of the phosphorexcited to emit the red light will degrade differently with theexcitation efficiency of the phosphor excited to emit the yellow light.As illustrated in FIG. 14, as the power of the laser light increases,the light emission efficiency of the red light filtered out from theyellow light will be higher than the light emission efficiency of thered light emitted by the excited phosphor excited to emit the red light,so the advantage of the improvement in brightness will also becomeincreasingly apparent; and here the dotted line represents the lightemission efficiency curve of the yellow light emitted by the excitedphosphor to emit the yellow light, and the solid line represents thelight emission efficiency curve of the red light emitted by the excitedphosphor to emit the red light.

The control unit controls the fluorescent wheel and the filter phosphorto rotate in synchronization, and in some embodiments of the disclosure,the fluorescent light emitted from the fluorescent wheel is transformedin direction by the first optical axis transformation lens, which is adichroscope.

As for a projection display device using the light source device, oneframe of image is output each time the fluorescent wheel and the filterwheel are rotated by one round, that is, the frequency at which thefluorescent wheel and the filter wheel are rotated is set the same asthe display frequency of the projection display device, and thedisplaying effect of the image may be better at a higher frequency. Forexample, the fluorescent wheel and the filter wheel are rotated by 120rounds per second at the display frequency of 120 Hz.

In operation, the control unit controls the fluorescent wheel and thefilter phosphor to initially rotate until they reach a preset rotationspeed, and then starts the laser and keeps the laser started while theimage is being displayed.

Accordingly a part of the laser light in the blue band is transmittedfrom the transmission section of the fluorescent wheel, and thefluorescent light emitted by the phosphor excited by the laser light isreflected by the fluorescent wheel, and there are different light pathsof the two parts of the light, so the light converging device accordingto some embodiments of the disclosure may further include a plurality ofoptical axis transformation lenses configured to focus the transmittedlaser light and the fluorescent light reflected by the first opticalaxis transformation lens onto the same light path. As illustrated inFIG. 9, for example, the light converging device may include a secondoptical axis transformation lens 24 a, a third optical axistransformation lens 24 b and a fourth optical axis transformation lens24 c, and the three optical axis transformation lenses may be reflectionmirrors or dichroscopes configured to refract and reflect the laserlight in the blue band transmitted from the transmission section of thefluorescent wheel so that finally the laser light is transmitted throughthe first optical axis transformation lens 21 into the focusing lens 27where the laser light is converged together with the fluorescent lightemitted from the excited phosphor and reaches the filter wheel.

A collimation lens group 22 is further arranged nearby the front sideand/or the back side of the fluorescent wheel; the second optical axistransformation lens parallel to the first optical axis transformationlens is arranged at the light emission side of the collimation lensgroup nearby the back side of the fluorescent wheel; the third opticalaxis transformation lens is arranged perpendicular to the second opticalaxis transformation lens; and the fourth optical axis transformationlens is arranged perpendicular to the third optical axis transformationlens and parallel to the first optical axis transformation lens.

The light converging device may further include an image conversion lensgroup 25 arranged between the second optical axis transformation lensand the fourth optical axis transformation lens; and a diffusion sheet30 arranged at the light emission side of the image conversion lensbetween the third optical axis transformation lens and the fourthoptical axis transformation lens to diffuse the laser light asappropriate to thereby make light spots uniformly distributed.

As illustrated in FIG. 9, there is a systematic diagram of the lightsource device according to some embodiments of the disclosure, which mayoperate as follows: laser light in blue band generated by a laser (thelaser arrays 11) is shaped by the beam shaping device including thereflection mirror 12, the convex lens 13 and the concave lens 14, andthe shaped laser light is emitted to the first optical axistransformation lens. Optionally the shaped laser light may pass adiffusion sheet 29 before being emitted to the first optical axistransformation lens, so that the laser light may be diffused asappropriate to thereby make light spots distributed uniformly. The laserlight emitted to the first optical axis transformation lens istransmitted through the first optical axis transformation lens, adjustedby the collimation lens group and emitted to the fluorescent wheel. Onone hand, the laser light in the blue band is transmitted by thetransmission section of the fluorescent wheel and adjusted by thecollimation lens group nearby the back side of the fluorescent wheel,then emitted to the second optical axis transformation lens, andtransformed by the second optical axis transformation lens, the thirdoptical axis transformation lens and the fourth optical axistransformation lens, and image-converted by the image conversion lensgroup, in the light converging device, and then emitted to the firstoptical axis transformation lens, transmitted through the first opticalaxis transformation lens and emitted to the focusing lens in the lightconverging device; and on the other hand, the laser light excites thephosphor on the fluorescent wheel to thereby excite and reflect thefluorescent light in the yellow band and the fluorescent light in thegreen band, and the fluorescent light is reflected by the first opticalaxis transformation lens to the focusing lens in the converging device.Thus the transmitted laser light in the blue band and the emittedfluorescent light in the yellow band and the green band are converged bythe light converging device onto the same light path and emitted to thefilter wheel. The light emitted to the filter wheel is transmitted bythe transparent section or filtered by the filter section of the filterwheel to generate the light in the four primary colors of red, green,blue and yellow. The filtering process has been described above, so arepeated description thereof will be omitted here. The generated lightin the four primary colors enters an optical rod 28.

Based on the characteristics of the spectrum of the natural light, onone hand, a spectrum of light in one band may include a part of aspectrum of light in an adjacent band thereto, and with the light sourcedevice according to the disclosure, the spectrum of the light in theyellow band may include the characteristic of a part of the spectrum ofthe light in the red band, and the fluorescent wheel may cooperate withthe filter wheel so that after the phosphor, on the fluorescent wheel,excited by the laser light to emit the yellow light is excited by thelaser light to emit the yellow light, the yellow light may betransmitted by the transparent section on the filter wheel, and the redlight may be filtered out by the red filter section on the filter wheelfrom the yellow fluorescent light, so that the light in the two colorsmay be extracted from the fluorescent light in the single band; and onthe other hand, when light at a long wavelength is excited using lightat a short wavelength, the efficiency of the excited light will be lowerif the wavelength of the light at the long wavelength is longer, andfollowing this principle, the laser light excites the phosphor excitedto emit the yellow light, and the red light is filtered out from theemitted yellow light, and since the wavelength of the yellow light isshorter than the wavelength of the red light, there will be higher lightemission efficiency of the red light filtered out from the yellow lightas compared with the red light generated using the excited phosphorexcited by the laser light to emit the red light; and the energyefficiency of the light in the other colors and thus the overallbrightness of the light source device may be improved given theimprovement above in light emission efficiency of the red light at thesame energy efficiency.

As for a projection display device in the prior art, a light sourcedevice is typically provided therein with a focusing lens including aspherical lens with a light emission half-angle ranging from 25° to 30°,here the light emission half-angle is half of the angle at which thelight emits from the lens; and as for an ultra-short-focus projectiondisplay device, there may be significant vignetting in the lens, and inorder to better control the vignetting and to reduce the angle of lightincident on a optical rod, the angle of the spherical radius of thefocusing lens needs to be reduced. In some embodiments of thedisclosure, the light emission half-angle of the focusing lens 27 is 23°so that the brightness of the projected light may become higher and thusthe operating efficiency of the projection lens may be improved.

The four colors of red, green, blue and yellow may be used as primarycolors to synthesize a number of other natural colors in a wider colorgamut, thereby achieving a technical effect of widening the displaycolor gamut of the projection display device.

Some further embodiments of the disclosure further provide a projectiondisplay device including the light source device according to theembodiments above of the disclosure, and the light source device mayinclude a laser for generating laser light, a fluorescent wheel, afilter wheel and a control unit; the fluorescent wheel includes at leastone reflection section, and at least one transmission section capable oftransmitting the laser light; at least one phosphor capable of beingexcited by the laser light to emit light in a first wavelength band, andat least one phosphor capable of being excited by the laser light toemit light in a second wavelength band are attached on the surface ofthe reflection section; the filter wheel includes at least onetransparent section, at least one first filter section and at least onesecond filter section; and the control unit is configured to control thefluorescent wheel and the filter wheel to rotate in synchronization sothat the transparent section of the filter wheel corresponds to thetransmission section of the fluorescent wheel, and a part of thephosphor, on the fluorescent wheel, excited by the laser light to emitthe light in the first band, the first filter section of the filterwheel corresponds to another part of the phosphor, on the fluorescentwheel, excited by the laser light to emit the light in the first band,and the second filter section of the filter wheel corresponds to thephosphor, on the fluorescent wheel, excited by the laser light to emitthe light in the second band.

The light in the first band and the light in the second band may bevisible light applicable to the inventive solution, for example, thelight in the first band may be yellow light, green light, etc.; and thelight in the second band may be green light, yellow light, red light,etc. Moreover the first filter section may be a red filter section, agreen filter section, etc., and the second filter section may be a greenfilter section, a red filter section, etc.

Some embodiments of the disclosure further provide a projection displaydevice including the light source device above. It shall be noted thatthe projection display device may also include a housing, a heat sink, amicroprocessor and other components in addition to the light sourcedevice above. The projection display device including the light sourcedevice above may use the four colors as primary colors to synthesize anumber of other colors in a wider color gamut for a better effect ofdisplaying an image.

Some embodiments of the disclosure have at least the following technicaleffects or advantages.

The phosphor, on the fluorescent wheel, capable of being excited to emitthe yellow light corresponds to the transparent section and the redfilter section on the filter wheel, and when the phosphor is excited bythe laser light to emit the yellow fluorescent light, the transparentsection may transmit the yellow light, and the filter section may filterout the red light; the phosphor, on the fluorescent wheel, capable ofbeing excited to emit the green light corresponds to one green filtersection on the filter wheel, and when the phosphor is excited by thelaser light to emit the green light, the green light is filtered out;and the transmission section on the fluorescent wheel corresponds to thetransparent section on the filter wheel to thereby transmit the laserlight, so that finally the light in the four colors may be generatedfrom the light emission face of the filter wheel according to thesetting on and the correspondence relationship between the fluorescentwheel and the filter wheel. Since the light in the four primary colorsincluding the additional yellow color is synthesized into a number ofcolors, there will be a wider color gamut of the synthesized lightsource device than that of a number of colors into which the threeprimary colors are synthesized. Moreover since the efficiency ofconversion into light energy at a corresponding wavelength due toexcitation will become lower at a longer wavelength, thus in thetechnical solution according to some embodiments of the disclosure, thered light is filtered out by the red filter section from the yellowfluorescent light, and since the wavelength of the yellow light isshorter than the wavelength of the red light, there will be higher lightenergy, and thus higher light emission efficiency and higher brightness,of the red light filtered out from the yellow light generated by theexcited phosphor excited by the laser light to emit the yellow light, ascompared with the red light generated by the excited phosphor excited bythe laser light to emit the red light. Also due to the improvement inlight emission efficiency of the red light, the angle, on the circle,occupied by the phosphor excited to emit the yellow light may be lowerthan the angle occupied by the phosphor excited to emit the red lightwith the same energy efficiency, thus the proportions of the phosphorsexcited to emit the yellow light and the green light may be increased asappropriate, and the energy conversion efficiency (the light emissionefficiency) of the yellow light and the green light emitted due toexcitation may be improved than before. Moreover since the wavelengthsof both the yellow light and the green light are shorter than that ofthe red light, there will be higher conversion efficiency of the yellowlight and the green light emitted due to excitation than that of the redlight, thus the light energy of the light in these colors may beincreased to thereby improve the brightness of the light in these colorsso as to improve the overall brightness of the light source device.

With the light source device and the projection display device accordingto some embodiments of the disclosure, the red light is filtered outfrom the yellow light to thereby generate the red light with higherlight emission efficiency, and the yellow color is added as the fourthprimary color to be synthesized with the red light, the green light andthe blue light into a number of colors, thus the light emissionefficiency of the red light may be improved so as to further improve thelight emission efficiency of the light in the other colors, so that thefour primary colors may be synthesized into a number of colors withhigher overall brightness in a wider color gamut.

Although the preferred embodiments of the disclosure have beendescribed, those skilled in the art benefiting from the underlyinginventive concept may make additional modifications and variations tothese embodiments. Therefore the appended claims are intended to beconstrued as encompassing the preferred embodiments and all themodifications and variations coming into the scope of the disclosure.

Evidently those skilled in the art may make various modifications andvariations to the disclosure without departing from the spirit and scopeof the disclosure. Thus the disclosure is also intended to encompassthese modifications and variations thereto so long as the modificationsand variations come into the scope of the claims appended to thedisclosure and their equivalents.

The invention claimed is:
 1. A light source device, comprising a laser for generating laser light, a fluorescent wheel, a filter wheel and a control unit, wherein: the fluorescent wheel comprises a reflection section, and a transmission section for transmitting the laser light; wherein a first phosphor and a second phosphor are attached on a surface of the reflection section, and the first phosphor is configured to be excited by the laser light to emit yellow light and the second phosphor is configured to be excited by the laser light to emit green light; the filter wheel comprises a transparent section, a red filter section and a green filter section; and the control unit is configured to control the fluorescent wheel and the filter wheel to rotate in synchronization, and the laser light emitted from the transmission section of the fluorescent wheel and a part of the yellow light emitted from the first phosphor enter into the transparent section of the filter wheel, another part of the yellow light emitted from the first phosphor enter into the red filter section of the filter wheel, and the green light emitted from the second phosphor enter into the green filter section of the filter wheel.
 2. The light source device according to claim 1, wherein the laser light is in blue band.
 3. The light source device according to claim 1, wherein the fluorescent wheel comprises two transmission sections centrally symmetrically distributed, two first portions where the first phosphor attached, and two second portions where the second phosphor attached, the two first portions are centrally symmetrically distributed, and the two second portions are centrally symmetrically distributed; the filter wheel comprises two transparent sections centrally symmetrically distributed, two red filter sections centrally symmetrically distributed, and two green filter sections centrally symmetrically distributed.
 4. The light source device according to claim 3, wherein one of the transmission sections, one of the first portions and one of the second portions occupy together half of the circle of the fluorescent wheel; and one of the transparent sections, one of the red filter sections and one of the green filter sections occupy together half of the circle of the filter wheel.
 5. The light source device according to claim 1, wherein the filter wheel comprises two transparent sections distributed opposite around the center of the filter wheel.
 6. The light source device according to claim 1, wherein a collimation lens group is arranged nearby at least one of the front side and the back side of the fluorescent wheel.
 7. The light source device according to claim 1, wherein the fluorescent wheel comprises one transmission section, one first portion where the first phosphor attached, and one second portion where the second phosphor attached.
 8. The light source device according to claim 7, wherein the filter wheel comprises two transparent sections distributed opposite around the center of the filter wheel.
 9. The light source device according to claim 8, wherein the laser light emitted from the transmission section of the fluorescent wheel enter into one of the two the transparent sections of the filter wheel, the part of the yellow light enter into another one of the two the transparent sections of the filter wheel.
 10. A projection display device, comprising a laser for generating laser light, a fluorescent wheel, a filter wheel and a control unit, wherein: the fluorescent wheel comprises a reflection section, and a transmission section capable of transmitting the laser light; wherein a first phosphor and a second phosphor are attached on a surface of the reflection section, and the first phosphor is configured to be excited by the laser light to emit yellow light and the second phosphor is configured to be excited by the laser light to emit green light; the filter wheel comprises a transparent section, a red filter section and a green filter section; and the control unit is configured to control the fluorescent wheel and the filter wheel to rotate in synchronization, and the laser light emitted from the transmission section of the fluorescent wheel and a part of the yellow light emitted from the first phosphor enter into the transparent section of the filter wheel, another part of the yellow light emitted from the first phosphor enter into the red filter section of the filter wheel, and the green light emitted from the second phosphor enter into the green filter section of the filter wheel.
 11. The projection display device according to claim 10, wherein the laser light is in blue band.
 12. The projection display device according to claim 10, wherein the fluorescent wheel comprises two transmission sections centrally symmetrically distributed, two first portions where the first phosphor attached, and two second portions where the second phosphor attached, the two first portions are centrally symmetrically distributed, and the two second portions are centrally symmetrically distributed; the filter wheel comprises two transparent sections centrally symmetrically distributed, two red filter sections centrally symmetrically distributed, and two green filter sections centrally symmetrically distributed.
 13. The projection display device according to claim 12, wherein one of the transmission sections, one of the first portions and one of the second portions occupy together half of the circle of the fluorescent wheel; and one of the transparent sections, one of the red filter sections and one of the green filter sections occupy together half of the circle of the filter wheel.
 14. The projection display device according to claim 10, wherein the filter wheel comprises two transparent sections distributed opposite around the center of the filter wheel.
 15. The projection display device according to claim 10, wherein the fluorescent wheel comprises one transmission section, one first portion where the first phosphor attached, and one second portion where the second phosphor attached.
 16. The projection display device according to claim 15, wherein the filter wheel comprises two transparent sections distributed opposite around the center of the filter wheel, and the laser light emitted from the transmission section of the fluorescent wheel enter into one of the two the transparent sections of the filter wheel, the part of the yellow light enter into another one of the two the transparent sections of the filter wheel.
 17. A projection display device, comprising a laser for generating laser light, a fluorescent wheel, a filter wheel and a control unit, wherein: the fluorescent wheel comprises a reflection section, and a transmission section for transmitting the laser light; wherein a first phosphor and a second phosphor are attached on a surface of the reflection section, and the first phosphor is configured to be excited by the laser light to emit a first light in a first band, and the second phosphor is configured to be excited by the laser light to emit a second light in a second band; the filter wheel comprises a transparent section, a first filter section and a second filter section; and the control unit is configured to control the fluorescent wheel and the filter wheel to rotate in synchronization, and the laser light emitted from the transmission section of the fluorescent wheel and a part of the first light emitted from the first phosphor enter into the transparent section of the filter wheel, another part of the first light emitted from the first phosphor enter into the first filter section of the filter wheel, and the second light emitted from the second phosphor enter into the second filter section of the filter wheel.
 18. The projection display device according to claim 17, wherein the laser light is blue laser light, and the second light is green light.
 19. The projection display device according to claim 17, a first filter section is a red filter section, the first light is light which can be filtered by the red filter section to generate red light.
 20. The projection display device according to claim 17, wherein the fluorescent wheel comprises one transmission section, one first portion where the first phosphor attached, and one second portion where the second phosphor attached; wherein the filter wheel comprises two transparent sections distributed opposite around the center of the filter wheel; the laser light emitted from the transmission section of the fluorescent wheel enter into one of the two transparent sections of the filter wheel, the part of the first light enter into another one of the two transparent sections of the filter wheel. 